This invention relates to construction panels for structural support systems having high strength to weight ratios and excellent insulating properties. The construction panels are primarily for use as exterior walls but may also be used for interior walls, partitions, ceilings and the like.
Currently, buildings are being constructed from a wide variety of materials. Among the more common are wood, cinder block, brick, concrete, metal and glass. Each has particular advantages and disadvantages. Wood, while relatively easy to work with, is flammable, requires the labor of skilled carpenters, and is becoming increasingly expensive. Cinder block and brick, although quite durable are quite heavy, thus requiring high transportation costs. In addition, working with brick and block requires the attention of skilled masons over long periods of time. Concrete is awkward to transport, comparatively expensive and requires the use of special construction techniques and building equipment. Metal panels are poor insulators and require the services of welders, riveters or other personnel to fasten the panels together and to the supporting structure by bolts, rivets or the like. Glass is breakable, hard to transport and is not a good insulator. Because of these disadvantages, new materials have been and are being developed to replace the traditional building materials.
Recently some states have passed new laws mandating that new structures must meet certain energy efficiency standards including high "R" value insulation standards. Additionally, the cost of lumber is escalating and natural resources are being depleted. Proper insulation of a building leads to conservation of both energy and natural resources while at the same time meeting the new energy efficiency standards being written into law.
Various prior art methods of insulating buildings have been proposed. The most common form of insulation is foilbacked fiberglass. Rolls of this material having various degrees of thicknesses are unrolled at a job site, cut to size and then mounted between adjacent wall studs. For preconstructed structures, insulating material may be blown between the outer facing and the inner walls of a building to the desired density and R value.
Another technique of providing adequate insulation for buildings is to incorporate insulating material in prefabricated building panels. These panels offer the advantages of good insulating properties, mass production, and ease of on-site assembly of the panels, among other. These panels generally comprise a core of insulating material surrounded by structurally rigid panels. The core of insulating material may comprise balsa wood, glass wool, foamed or expanded polymeric materials such as polystyrene, polyvinyl chloride, polyurethane, etc. The core material may be surrounded by panel members comprising first and second major face members and side and end walls of such materials as plywood, metal, resin and resin reinforced with fibrous glass rovings, etc. Generally, these panels are strong, lightweight and provide proper insulating properties while using less wall space.
These modular panels also have some disadvantages. Since the foam used in forming the core is not elastic, once it is compressed, a space develops between the core and facing member. This results in weakened structural integrity and may be responsible for such conditions as warping, buckling and cracking of the face member or of the entire panel. An additional disadvantage is that the major face members generally cannot withstand a great amount of load-bearing pressure as may be encountered when the panels are used as load-bearing members. To make the panels stronger, various reinforcing means have been incorporated within them. U.S. Pat. No. 4,078,348 (Rothman) includes a discussion of patents that are representative of the way in which the prior art has attempted to overcome the problems and disadvantages associated with foamed core sandwich-type panels.
U.S. Pat. No. 4,163,349 (Smith) shows an insulating building panel including an insulating core and having an exterior skin on one side and an interior skin on the other side. The skins overlap the core about its periphery and, at the sides of the panel, extend from the core a distance to receive a portion of a bearing post to which adjacent panels are connected. U.S. Pat. No. 4,567,699 (McClellan) relates to a prefabricated building system made up of a plurality of prefabricated panels. Each panel includes a formed body of insulating material having a top, a bottom, sides, a front face and a back face. At least one hollow tubular load-bearing member is embedded in the body intermediate the sides and faces thereof and extends vertically between the top and bottom. The tubular load-bearing member has a slot in the top and bottom. The slots have their axis generally parallel to the front and rear faces of the body. A bottom member is provided along the floor and has an upstanding flange extending into the slot of the bottom of the tubular member and a top member extends along the top of the panels and has a flange extending downwardly into the slots in the top of the tubular load-bearing members. The load-bearing members have a length greater than the length of the body so that vertical loads are not transmitted to the body.
Additional examples of modular wall sections employing foam insulation are shown in U.S. Pat. Nos. 3,828,502 (Carlsson); 3,791,912 (Allard); 3,562,985 (Nicosia) and 3,449,879 (Bloom).
Despite the several alternatives for providing prefabricated panels in building systems, there is still a need for a construction panel and building system which is less expensive to produce because of conservation of materials, requires less labor for erection at the work site, costs less to transport to the work site and minimizes energy losses. The present invention is directed toward filling that need.